The Dialysis Outcomes and Practice Patterns Study (DOPPS) is an important longitudinal study of ESRD patients in multiple countries, and is the source of much respected epidemiologic data on dialysis patients worldwide. Interestingly, the DOPPS estimated the crude 1-year mortality rate of ESRD patients in the U.S. to be a whopping 21.7%, which compares quite poorly to the rates in Japan (6.6%) and Europe (15.6%). This difference persists even after controlling for comorbid conditions. An editorial in this month’s JASN by Foley and Hakim tries to tackle this touchy topic of American inferiority in the ESRD setting in an organized fashion.
A 2006 cross-sectional study by Yoshino et al using an international WHO mortality database helps to get at this question by noting a close correlation between all-cause mortality rates and cardiovascular mortality in the general population and showed that this correlation is even stronger within dialysis patients. This, it appears that at least some of the reason that U.S. ESRD patients do poorly is because of the relatively high rate of cardiovascular disease in the general population here.
There remain, however, other variables between countries which could also potentially explain the difference in mortality. U.S. patients tend to spend less overall time on dialysis than in Japan, for instance, and the U.S. also performs poorly in terms of having a low percentage of patients who begin dialysis with catheters as opposed to AV fistulas. Dialysis units in the U.S. are often staffed by a high percentage of dialysis technicians who have less formal training than dialysis nurses, which are required in greater numbers in Europe. I have also suspected that in the U.S. we may tend to dialyze the very elderly or the very ill with greater frequency than in other countries, which would obviously tend to make our numbers look worse. Explaining the mortality discrepancy likely has a complex answer, but it makes sense to try and figure out what aspects of our dialysis care might be improved to help lessen the mortality difference.